Treatment of petroleum distillates



TREATPVENT OF PETROLEUM DISTILLATES Edward J. Bicek, La Grange, IlL, assignor to Universal Oil Products Company, Des Plaines, lll., a corporation of Delaware No Drawing. Application April 5, 1954, Serial'No. 421,200

2 Claims. (Cl. 196--23) This invention relates to the treatment of petroleum distillates and more particularly to the removal of arsenic therefrom.

While the present invention may be utilized for the treatment of kerosene, diesel oil, fuel oil, lubricating oil, etc., it is particularly advantageous for the treatment of gasoline fractions. A recently developed process for improving the octane characteristics of gasoline or naphtha comprises reforming the same in the presence of a catalyst containing a noble metal and particularly platinum. The presence of arsenic in the gasoline or naphthe and its subsequent contact with the platinum cata lyst is objectionable because the arsenic appears to deactivate the catalyst and therebyito detrirnentally affect the reforming process.

The gasoline may comprisea full boiling range gasoline having initial boiling point of from about 70 to about 110 F. and an end boiling point of from about 375 to about 425 F., or it may comprise any selected fraction thereof and particularly a naphtha fraction having an initial boiling point of from about 150 to about 300 F. and-an end boiling point of from about325 to about 450 F. The gasoline or naphtha will be referred to herein a gasoline fraction. The gasoline fraction may be substantially parafiinic including straight run gasoline, natural gasoline, etc. or it may be substantially unsaturated including thermally cracked gasoline, catalytical-ly crackedigasoline, coker distillate, etc., or mixtures thereof.

While the present invention is particularly advantageous for use in pretreating gasoline fractions prior to reforming in the presence of a catalyst containing a noble metal, it is understood that it also will find applicability in the treatment of other petroleumdistill-ates or for treating gasoline fractions for other subsequent uses.

In one embodiment the present invention relates to a process for removing arsenic from petroleum distillate which comprises treating said distillate with peroxide and acid.

In a specific embodiment the present invention relates to a process for the removal of arsenic from a gasoline fraction which comprises treating said gasoline fraction with cumene hydroperoxide and acetic acid, and thereafter treating the gasoline fraction with water.

In accordance with the present invention, arsenic is removed from petroleum distillate by treatment both With a peroxide and an acid. In a preferred embodiment this treatment serves to convert the arsenic in the petroleum distillate into a form which is readily removed by subsequent Water washing and thus, in a preferred embodiment of the invention, the treatment with peroxide and acid is followed by treatment with water.

Any suitable peroxide may be used in accordance with the present invention and, in a preferrcd'embodiment, comprises a peroxide soluble in the petroleum distillate. Cumene hydroperoxide is particularly preferred forvuse in accordance with the present process. Other organic nited States Patent 2,782,143 Patented Feb. 19, 1957 peroxides include, for example, acetyl peroxide, dimethyl peroxide, methyl ethyl peroxide, dipropyl peroxide, ditertiary butyl peroxide, acetyl benzoyl peroxide, propionyl peroxide, butyryl peroxide, lauroyl peroxide, benzoyl peroxide, tetralin peroxide, urea peroxide, tertiary butyl perbonzoate, tertiary butyl hydroperoxide, methyl cyclohexyl peroxide, etc. Of the inorganic peroxides, hydrogen peroxide is preferred although, in some cases, the peroxide may comprise sodium peroxide, potassium peroxide, calcium peroxide, barium peroxide, strontium peroxide, etc. It is understood that these various peroxides are not necessarily equivalent and that mixtures of peroxides may be employed.

In another embodiment of the invention the peroxide may be formed in situ in the petroleum distillate in any suitable manner. For example, the peroxide may be produced by suitable oxidation induced by introduction of air or other oxygen-containing gas, heat treatment, treatment with ultra-violet light, etc. However, it generally is preferred :to add the desired peroxide to the gasoline because, in this manner, more accurate control of the amount of peroxide being added is obtained and also because this method eliminates possible side reactions which may occur during oxidation of the petroleum distillate to form the peroxide in situ.

Any suitable acid may be used in accordance With the present invention and, in one embodiment, preferably comprises a soluble acid. Organic acids include formic, acetic, propionic, butyric, valeric, chloroacetic, dichloroacetic, trichloroacetic, fiuosulfonic acids, etc., caproic, heptylic, caprylic, pelargonic, lauric, myris-tic, palmitic, .stearic, oleic, ricinoleic, linoleic benzoic, chlorobenzoic, toluic, anisic, etc. inorganic acids include sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, etc. It is understood that these acids are not necessarily equivalent and that mixtures of acids may be used.

In another-embodiment, the additive may comprise a compound having both peroxide and acid components including, for example, pe-racetic acid, persuccinic acid, peroxybenzoic acid, perchloric acid, persulfuric acid, etc. It is understood that two or more of these peracids may be used and also that they are not necessarily equivalent. In some cases the peracid or peracids may be used along with one or more of the peroxides and/ or acids hereinbefore set forth.

in another embodiment, the peroxide and/or acid may be oomposited with a suitable supporting or carrying material, preferably comprising a porous solid, including, for example, silica gel, alumina gel, clays including fuller?s earth, bentonite, feldspar, kieselguhr, bauxite, dispore, etc., synthetic composites, of one or more oxides of silicon, aluminum, magnesium, zirconium, thorium, vanadium, titanium, etc., as for example, silicaalumina, silica-zirconia, silica-alumina-zirconia, silicamagnesia, silica-alumina-magnesia, alumina-zirconia, alumina-magnesia, etc. The composite of the peroxide or acid may be prepared in any suitable manner including, for example, soaking the carrying material in a solution of the peroxide or acid, percolating the peroxide or acid over the supporting mate-rial, etc. The supporting. material may comprise particles of uniform or irregular size and shape and may be formed by grinding, pelleting, extrusion, spray drying, etc.

The amount of peroxide and/or acid to be employed will depend upon the arsenic concentration of the petroleum distill-ate. Suflicient amounts will be utilized to effecttthe desired reduction in arsenic. The propertions of peroxide to acid likewise may vary considerably -oftheother.c V

Treatment of the petroleum distillate with the peroxide and acid may be effected in any suitable manner and will depend upon the form in which the peroxide and acid are used. When both the peroxide and acid are liquid, they may be commingled with the petroleum distillate, either simultaneously or first one and then the other, and the mixture preferably intimately mixed by suitable mechanical stirring, recirculation by pumping out and back into the treating zone, injecting a gas into the mixture, etc. When the peroxide and/or acid is composited with a solid support, the petroleum distillate is passed therethrough, either in upward or downward flow.

The treatment of the petroleum distillate may be effected at any suitable temperature. Usually atmospheric temperature is satisfactory for most treatments but, when desired, elevated temperature may be employed. The ele vated temperature in general will not be above about 500 F. The pressure may range from atmospheric to 1000 pounds or more and preferably is sufficient to maintain the mixture in substantially liquid phase. The process may be effected in batch or continuous type of operation.

As hereinbefore set forth, this treatment, in one embodiment, converts the arsenic compounds in the petroleum distillate into a form which is readily removed by water washing. Therefore, in a preferred embodiment, after treatment with the peroxide and acid, the petroleum distillate is washed or otherwise contacted with water. When the peroxide and/or acid are composited with a solid support, arsenic removal may include retention of the arsenic in and/ or on the solid treating agent. When sufficient arsenic is removed in this manner, subsequent water washing of the petroleum distillate may be unnecessary. in another embodiment, fractionating, stripping, clay treating, etc, either with or without prior or subsequent water washing, may be employed.

The use of both the peroxide and acid offers numerous advantages in the treatment of petroleum distillates to re move arsenic therefrom. Apparently the peroxide and acid exert a synergistic effect in obtaining arsenic removal. This is particularly advantageous in petroleum distillates containing arsenic in a form which is difficult to remove.

As hereinbefore set forth, removal of arsenic from a gasoline fraction is particularly desirable when the gasoline fraction is subsequently subjected to reforming in the presence of a catalyst containing a noble metal. While the noble metal may comprise platinum, palladium, gold, silver, etc., a recent reforming process utilizes platinum in a concentration of from about 0.01% to about 1% composited with a solid support. It is understood that the platinum may be present in higher concentrations, which may range up to by weight or more. Of these reforming processes, a preferred process comprises one utilizing a catalyst comprising alumina, from about 0.01% to about 1% by weight of platinum and from about 0.1% to about 8% by weight of combined halogen and preferably from about 0.1% to about 3% by weight of combined fluorine. The reforming process generally is effected at a temperature of from about 800 to 1000 F. or more, a pressure of from about atmospheric to 1000 pounds per square inch, and a weight hourly space velocity of from about 0.1 to 10 or more. The process preferably is effected in the presence of hydrogen, generally in a ratio of from about 0.1:1 to about 10:1 or more mols of hydrogen per mol of hydrocarbon in the reaction zone. In another embodiment, these catalysts are particularly applicable to the conversion of naphthenes into aromatics. It is understood that the novel features of the present invention may be employed for the pretreatment of a charging stock for any conversion in the presence of a noble metal catalyst or for any other de: sired use;

The following examples are introduced to illustrate further the novelty and utility of the present invention but not with the intention of unduly limiting the same.

4 EXAMPLE I This example is present to show the detrimental effect of arsenic on a catalyst comprising alumina, 0.3% by weight of platinum and about 0.2% by weight of combined fluorine. To a portion of this catalyst, arsenic was added in a concentration of 0.0025 gram atoms per 50 grams of catalyst. The arsenic was added as arsenic pentoxide in ammonical solution by dissolving the required amount in 50 ml. of water and pouring over 50 grams of the catalyst. The catalyst was allowed to stand for one half hour, then was dried on a water bath and finally calcined for 3 hours in a muffle furnace at 932 F.

The catalysts in this example were utilized for the aromatization of a Mid-Continent naphtha having an A. l. i. gravity at 60 F. of 52.7, an aromatic content of 8.8% and a boiling range of 229 to 387 F. The aromatization was effected at a temperature of 977 F., a superatmospheric pressure of 300 pounds per square inch and a hydrogen to hydrocarbon molar ratio of 1.75:1.

Catalyst A comprised the alumina-platinun'l-halogen composite as described above but not containing the arsenic, Catalyst B comprised the catalyst containing the arsenic as described above.

in the aromatization runs, catalyst A produced an average of 48.3% by weight of aromatics. in contrast. catalyst B under the same conditions produced only 23.6% by weight of aromatics. It thus will be noted that the arsenic reduced the aromatization activity of the catalyst to less than half of the catalyst not containing arsenic.

EXAMPLE II The gasoline used in this example was a West Virginia straight run gasoline which had an arsenic content of about parts per billion. Several 250 ml. samples of this gasoline were treated as follows: To one sample of the gasoline, one ml. of cumene hydroperoxide was added. To another sample of the gasoline one ml. of glacial acetic acid was added. To a third sample of the gasoline both one ml. of cumene hydroperoxide and one ml. of glacial acetic acid were added. Each of these samples were thoroughly mixed, water washed, and then both the water and the naphtha were analyzed for arsenic contents. The results of these analyses are reported in the following table.

From the above data it will be noted that the use of both cumene hydroperoxide and glacial acetic acid served to reduce the arsenic content of the naphtha to 4 parts per billion. On the other hand, the arsenic remaining in the naphtha was 68.8 and 108 parts per billion, respectively, when using only cumene hydroperoxide or glacial acetic acid.

EXAMPLE ill The hydrogen peroxide used in this example is impregnated on silica particles. 25 this. of a 30% solution of hydrogen peroxide added to 25 ml. of silica par ticles, the excess solution filtered off, and the wet silica. particles are mixed with 11 ml. of dry silica particles to form a free flowing mix. Hydrochloric acid is added to a sample of gasoline containing arsenic, and the gasoline containing the acid is then passed through the hydrogen peroxide-silica particles, after which the gasoline is washed with water. This treatment will serve to reduce the arsenic content of the gasoline to substantially zero.

I claim as my invention:

1. A process for removing arsenic from a gasoline fraction which comprises treating said gasoline fraction with cumene hydroperoxide and acetic acid, and thereafter water washing the gasoline.

2. A process which comprises treating a gasoline fraction containing arsenic with both cumene hydroperoxide and glacial acetic acid, thereafter treating the gasoline fraction with water, and subjecting the treated gasoline fraction reduced in arsenic to reforming in the presence of a platinum-containing catalyst.

References Cited in the file of this patent UNITED STATES PATENTS Liidecke Oct. 20, 1908 Axtell July 17, 1928 Gollmar Oct. 13, 1931 Eglofi June 12, 1934 Bretschger June 11, 1935 Fulton Oct. 29, 1935 Subkow Mar. 31, 1942 Holroyd et a1. Nov. 26, 1946 OTHER REFERENCES Gurwitseh et al.: Scientific Principles of Petroleum Technology (1932), page 173; published by Chapman 15 and Hall, London. 

1. A PROCESS FOR REMOVING ARSENIC FROM A GASOLINE FRACTION WHICH COMPRISES TREATING SID GASOLINE FRACTION WITH CUMENE HYDROPEROXIDE AND ACETIC ACID, AND THEREAFTER WATER WASHING THE GASOLINE.
 2. A PROCESS WHICH COMPRISES TREATING A GASOLINE FRACTION CONTAINING ARSENIC WITH BOTH CUMENE HYDROPEROXIDE AND GLACIAL ACETIC ACID, THEREAFTER TREATING THE GASOLINE FRACTION WITH WATER, AND SUBJECTING THE TREATED GASOLINE FRACTION REDUCED IN ARSENIC TO REFORMING IN THE PRESENCE OF A PLATINUM-CONTAINING CATALYST. 